Choke control for carburetors



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Patented Feb. 1, 1927.

UNITED STATES STUART G. GARRETT, F TULSA, OKLAHOMA.

CHOKE CONTROL FOR CARBURETORS.

Application filed September 23, 1926.

This invention relates to a choke control for carburetors.

The object of the invention is to provide an operating mechanism for thechokes of carburetors of the type which will automatically open by aspring or the like whereby the ieturn of the choke from a closed orpartially closed position to an open position will be retarded. In otherwords the operating mechanism provides for a variable speed of returnfrom a closed or partially closed to the normally open position of thechoke. In starting automobile engines of the type employing a chokenormally held open by a spring or the like the operator of the vehiclepulls the choke closed or partially closed but it immediately returns toopen position as soon as the operator releases hold of the same. Thisnecessitates repeated manipulation of the choke under some conditions.The present invention proposes to take advantage of the automaticopening of the choke but to do so without necessitating repeatedmanipulation thereof, and this is accomplished by retarding to thedesirable degree the return movement of the choke rod. i

A further object is to provide a device having these advantages andcapacities and which is of simple and durable construction,"

reliable and effective in operation and easy and comparativelyinexpensive to manufacture and install.

Other. objects and advantages reside in certain novel featnres oftheconstruction, arrangement and combination of parts which will behereinafter more fully described and particularly pointed out in theappended claims, reference being had to the accompanyingdrawings forminga part of this specification, and in wli'ichf Figure 1 is a fragmentaryperspective view showing the choke. control embodying the presentinvention in use on an automo- Figure 2 is a fragmentary view partly insection and partly in side elevation illustrating the details of thechoke control mechanism,

Figure 3 is a fragmentary detail perspective view of the novel form ofchoke rod,

Serial No. 137,303.

Fi ure 4 is a detail )ers )ectivc view showing one set of slips orwedges that may be employed, and

Figure 5 shows a slightly, modilied form of slip.

Referring to the drawings, the numeral 1 designates a carburetor of anautomobile in which the usual choke, not shown, is embodied. The chokeis spring-closed in accordance with the usual practice as for instanceby means of a spring 2 and has a lever 2 connected therewith and wherebyit may be opened against the tension of the spring which closes thesame.

The choke operating mechanism or control constituting the presentinvention is designated generally at 5 and comprises a cylindricalcasing 6 mounted on and secured to the instrument board of-the car bynuts 7. The upper end of the casing 6 carries a combined guide plug andtensioning device 27 and the lower end thereof has a reducing bushing 8threaded thereon and carrying a short cylinder 9 in which a guide plug10 is threaded. Through the guide bearings provided in the combinedtensioning device and guide plug 27' andin the guide plug 10, a chokerod, designated generally at 12, is slidably fitted. The upper end ofthe choke rod 9 has an operating knob 13 integral therewith and thelower end thereof is connected, as atl i, with a bell crank lever 15,the bell crank lever 15 being fulcrumed on a bracket 16 carried by astationary part of the automobile and being connected to a wire 18 whichis fastened at its lower end to the operating lever 2 of the choke ofthe carburetor.

The choke rod 12 adjacent the knob 13' has a thickened section 20, thethickened section 20 being connected with the main section 21 of the rodby means of a tapering section 22 of frusto-conical form. This taperingsection 22 is designed to and does co-act with a set of slips,designated generally at 23, the slips being positioned within thecylindrical casing 6 and seating against the upper end of the shortcylinder 9. The slips are tapered externally but have an internal boreof uniform cross sectional area. from end to end. Preferably the bore isof cylindrical form. The small end f the slip assembly enters the shortcylinder 9. As shown in Fig. 4 the set of slips 23 may comprise twoslips 24 but the number of slips may be varied, three or four segmentsor slips being used if desirable. -Fig. 5 illustrates that the set ofslips may consist of three slips 25.

The slips making up the set 23 are forced against the seatvp'rovided bythe short cylinder 9 by means of a coil spring" 26, one end of whichengages a washer 27 resting on the large end of the slips andthe'otherend of whichengages a washer 28. abutting the comhine'd'tensioning andguide plug 27. This plug 27 has a knurled or milled flange 28 tofacilitate turningof the same. Obviously, turning of the plug 27'results in a variationiof'the tension of the spring 26.

\Vhen the. choke rod is pulled upwardly the chokegis partially closed.'As soon as the operat "releases hold of the rod the spring associatedwith the choke tends to open the chokeand to pullthemod 12 downwardly.The downward movement of the rod occurs freely. at 'first but as Soonvas the tapered portion} 22,01? the rod engages the uniform internal'boreof the slips' 23 this closing movement is retarded and occurs at a veryslow rate'ofspeed, The rate of speed at which the closing.. movementoccurs de pends upon the spring 26 which may be regulated by turningtheplug 27, When the tapered portion, 2201 the rod QOfengages the uniforminternal bore or opening of the slips 23 it tends to forces-these slipsapart and this tendency is resisted by the com hined action of thespring 26 and cylinder 9. It is to be noted'tha't the slips "do not havea full seat in the cylinder 9 but only a line contact therewith and as,a result of this arrangement and of the co-action ofthe tapered section22 with the wall of the cylindrical or uniform. bore or opening of theslips the slips are permitted to and d0 grad ually spread rather thanlook and hold the rod against movement.

I claim:

1. A choke control for carburetors comprising a casing, means on thecasing afi'ord ing a seat, slips mounted on the seat, a choke rodextending through the casing and having a portion co-operable with theslips, and yieldable means tending to maintain the slips in yieldinggripping engagement with the choke rod.

2. A choke control for carburetors comprising a casing, means on thecasing afiording a seat, slips mounted, on the seat, a choke rodextending through the casing and having a portion co-operable with theslips, spring means tending to maintain the slips in yielding grippingengagement with the choke rod, and means for tensioning the said springmeans.

3. A choke control for carburetors comprising a casing having a seat,externally tapered slips co-operable with the seat, a choke rodextending through the casing, means on the casing providing a bearingfor the choke rod, said slips having a bore of uniform cross sectionfrom end to end, said choke rod having a tapered portion cooperable withthe uniform internal bore of the slips, and spring means for urging theslips into yieldable gripping engagement with the choke rod.

4. A choke control for carburetors comprising a casing, means on thecasing affordmg a seat, slips co-operable with the seat, plugs mountedon the casing and having bearings, a choke rod slidably fitted in thebearing, said choke rod being extended through the slips and engagedthereby, a

compression spring having one end engaged with the slips and the otherend engaged with one of the plugs, whereby the plug may be usedtotension the spring.

STUART G. GARRETT.

Ill)

